That is ALL part of the tactics and its VERY MUCH needed in the game. You can lose early, gain gold and at 50 roll and level up to get strong late game. But there is LOTS of downsides to this tactics even tho you get to pick item first. First its risky, you get strong guy that leveled and he gets you for 20+ hp, you need to ruin your economy to roll and get strong team but WAIT 6 other guys went for early game and picked champions they want so chance of you getting strong champ are weaker cause they took meta champs and you will mostly get weaker/off-meta champs and thats second problem, good champs are taken, also you have low hp so if somebody counters your comp youre already low and he can finish you easy. not to mention you can lose to neutral monsters which are BIG IMPORTANCE (krugs and wolfs mostly since by time of raptors youre strong or dead). Another problem is time limit, even if you have 70 gold and 30 hp there is 30 sec for preparation so if you go for rolling you dont have time to position and think so imo having 50 gold is bad unless youre on win streak and 80+ hp.
You can observe this quite well in meta and higher level players, in plat and diamond on start EVERYONE have champs with items and even roll to get at least 1 2 star unit cause hp is SOOO IMPORTANT while my second acc is in bronze and its so easy to get 5-8 win streak until they start to buff some champs. So carousel is great cause if you have plan you can time your power spike, you win some games and start losing before SECOND CAROUSEL, pick first and pickup gnar or akali and build around them but for that tactics you need to be very careful or you can lose easily. Plenty of more reasons why your statement is wrong